Electric disconnecting device



May 27, 1941. L. J. LINDE ELECTRIC DISCONNECTING DEVICE Original FiledDec. 12, 1936 Inventor: Leonard J. Linda.

His Attorney.

Patented May 27, 1941 ELECTRIC DISCONNEGTING DEVICE Leonard J. Linde, Drexel Hill, Pa., asslgnor to General Electric Company, a corporation of New York Original application December 12, 1936, Serial 2Claims.

My invention relates to electric disconnecting devices, more particularly to those of the plug and socket type having, for example, application to electric switchgear of the draw-out type wherein a circuit interrupting unit is connected and disconnected by bodily movement of the unit with respect to coacting circuit terminals.

My invention has for its principal object the provision of an improved disconnecting device which is electrically efficient, readily adaptable to varying operating conditions and simple and rugged in construction.

In accordance with my invention, the socket member of the disconnecting contact device, which may be fabricated or consist of a unitary member, is tubular or cylindrical in form and has substantially circular line contact with both the stationary and movable contact structures respectively so that eflicient electrical contact is maintained by said socket member at both contacts notwithstanding appreciable misalinement of said structures. More specifically, the aforesaid socket member is mounted with respect to an insulating housing or receptacle so that the coacting contacts are completely enclosed and insulated in the closed circuit position.

This application is a division of my application Serial No. 115,642 filed December 12, 1936, for Electric disconnecting devices, issued as Patent 2,176,178 on October 17, 1939.

My invention will be more fully set forth in the following description referring to the accompany ing drawing, and the features of novelty which characterize niy invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

Referring to the drawing, Fig. 1 is an elevational view of electric switchgear of the drawout type having disconnectingdevices embodying the present invention; Fig. 2 is an enlarged longitudinal view partly in section of one of the sets of disconnecting contacts shown by Fig. 1 in the closed circuit position; Fig. 3 is a longitudinal view partly in section of another form of disconnecting device embodying the present invention and Fig. 4 is a cross-sectional view taken along the line M of Fig. 2.

A particular form of draw-out type switchgear to which the present invention is applicable is illustrated by Fig. 1 wherein a pair of stationary circuit terminals generally indicated at l and 2 coact with a relatively movable circuit interrupting unit 3. The unit 3 normally controls an electric power circuit including the terminals l and 2. The circuit breaker unit 3 in the present 115,642. Divided and this April 19, 1939, Serial No- 268,738

application ent invention, specific disclosure thereof is believed to be unnecessary for an adequate and clear understanding of the invention.

As in the case of conventional draw-out type switchgear, the circuit breaker unit 3 is bodily movable between connected and disconnected positions with respect to the circuit terminals l and 2, and is guided and supported for horizontal reciprocal movement by means of a pair of stationary guide rails 5, between which the unit is positioned, and coacting rollers 6 mounted on the movable unit. Mounted in and extending through the base panel 4 of the breaker unit are the breaker terminals 1 and 8 corresponding to the terminals I and 2 respectively which are suitably mounted on the stationary supporting panel 9. The guide rails 5, which support the unit 3 in cantilever fashion, are suitably braced as at instance comprises a switch panel or base on air circuit breaker, for example. As the details of the circuit breaker form no part of the pres- The disconnecting devices for effecting the actual electrical contact between the circuit breaker unit 3 and the stationary terminals l and 2 are indicated at II and H respectively, Figs. 2 and 4 illustrating in greater detail the specific construction of the particular disconnecting contacts shown. Since the contacts are identical in design the disconnect device at Ill for interconnecting the terminals l and I will be described.

The disconnecting device consists essentially of a tubular cylindrical member I! composed of copper or other suitable conducting material open at the opposite ends for receiving contact elements l3 and I4 constituting parts of the stationary and movable terminals respectively. The contact surfaces of the contact elements I: and II coactiiig with the interior cylindrical contact surface of the member I! are of substantially spherical formation so that circular line contact is maintained at both ends of the member l2 notwithstanding appreciable misalinement of the terminals l and I. In other words, the contact connection at opposite ends of the cylindrical member i2 is in a certain sense analogous to a universal joint.

More specifically, in the form of disconnecting device shown by Figs. 2 and 4 the cylindrical conducting member i2 is composed of a plurality of separate conducting spring biased fingers or segments 95. This arrangement has particular application where a very compact design is desired, as for example, in cases where the spherical contact elements it and M of the fixed and movable conducting studs respectively are closely spaced in the connected position.

The mounting and insulating arrangement comprises a fixed insulating housing or receptacle l6 having an aperture H in the front panel thereof through which the conducting stud 18 of the movable unit extends in the connected position. The conductor stud i8 is suitably connected to the corresponding breaker terminal l9. Mounted behind the panel-like front of the receptacle I6 is an insulating housing 20 forming the contact receptacle 2| within which the disconnecting device is positioned. The stationary conductor stud 22 extends within the insulating housing 20 from the rear and is positioned therein by a collar 23 coacting with the usual terminal clamp exteriorly of the housing.

The disconnect contact elements [3 and I4 are interconnected or bridged in the connected -position illustrated by four separate conducting fingers or segments 15 which are held in position and biased into proper contact engagement by a surrounding helical spring 24, as best illustrated by Fig. 4. In normal operation the contact segments l are spaced as shown by Fig. 4 so that the spring 24 forces each segment individually into high pressure line-contact engagement with the spherical contact surfaces at I! and I 4. In case of misalinement of the conductor studs l8 and 22, it will be noted that proper contact is still maintained at both studs without appreciable change in spring tension, since the disconnect device allows free rotation at the contact surfaces of each stud.

The device is held in position simply by the coiled spring 24 and the front panel of receptacle I'B which prevents longitudinal displacement of the segments l5 by reason of the springretaining segment flanges I! (Fig. 4). This design is particularly advantageous where a comparatively simple, compact and rugged disconnecting device is required, in lieu of bolt connections for a simple, rugged interrupting unit. Accordingly, the socket element of the disconnecting device, although loosely positioned within the receptacle space 2| without the usual flexible electrical connections to the fixed terminal, is always in proper position for a connecting operation, notwithstanding limited misalinement of the movable terminal. It will furthermore be noted that the disconnect contacts are completely enclosed and insulated in the connected or closed circuit position.

Fig. 3 illustrates a modified form of the abovedescribed device wherein the segments 25 are positioned directly on a terminal stud. In this case a disk or collar member 26 is suitably secured as at 21 to the end of the stationary stud 22, and the segments are recessed at 28 for receiving a peripheral extension of thedisk. In this manner the surrounding springs 28, shown in the present instance as garter springs, lock the segments to the stationary stud without interfering with the flexibility of operation above described.

An insulating receptacle 3!! locked as shown to the fixed terminal encloses the sides and rear of the tubular conducting element or socket l2. In the connected or closed circuit position, the front is closed by an insulating cover or panel 3| carried by the movable terminal, so that the disconnect device when in connected position is completely closed and insulated.

In the operation of the disconnecting device above-described, the circuit breaker unit 3 in moving to the connected position forces the contact ll into the cylindrical member I2 against the friction due to the bias of the springs 2 or 29. The member I2 is suitably beveled as at l2- for guiding the contact II in case of inaccurate alinement of the terminals l and I.

Assuming improper alinement within practical limits, the member I2 is simply tilted in the direction of misalinement, the contact between members l2 and I! at the terminal I being substantially imaifected except that the line of contact engagement is shifted somewhat along the spherical contact surface. In order to insure maximum electrical efllciency, the contact members l2, l3 and H can be silver plated at the coacting contact surfaces, particularly where heavy currents are involved.

When the breaker unit 3 is to be disconnected the breaker is first opened in accordance with well-known practice and the unit then withdrawn along the guide rails 5 to its disconnected position. In order to provide a more compact design, the guide rails I are provided with folding extensions 5'', this feature forming no part of the present invention.

It should be understood that my invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electric disconnecting switch for electrically connecting and disconnecting terminals of a stationary circuit and a relatively movable unit respectively, said terminals including conductor studs, comprising a tubular contact of conducting material open at both ends thereof, said tubular contact being flexible with respect to its cross-sectional area and having resilient means for biasing the same toward a contracted position, and an insulating housing open only at one end loosely enclosing said tubular contact and rigidly secured to the conductor stud of one terminal, said one terminal engaging the inner contact surface of said tubular contact at one end thereof, said insulating housing freely receiving the other relatively movable terminal, said terminals having formed thereon coacting contact surfaces of'substantially spherical formation for maintaining uniform pressure, line contact between each of said terminals and said tubular contact within said insulating housing notwithstanding limited misalinemen-t of said terminals.

2. An electric disconnecting device for electrically connecting and disconnecting stationary and movable terminals of an electric circuit comprising a'tubular conducting member open at opposite ends thereof, said tubular member being flexible with respect to its cross-sectional area and having resilient means for biasing the same toward a contracted position, one of said terminals engaging the inner contact surface of said tubular member and having means for locking said tubular member with respect to said terminal for limited imiversal movement with respect thereto, an insulating receptacle rigidly mounted at one end on said terminal and partially enclosing said tubular member, said receptacle being open only at its opposite end, and an insulating cover member secured to the other of said terminals for coacting with the open end of said receptacle so that said disconnecting device is completely enclosed and insulated when said terminals are connected. 

